This invention relates to the formation of aircraft seat back structural elements. The invention essentially includes the steps of combining in a novel manner two features of current composite seat backs in a single construction. Essentially, the seat back diaphragm is combined with a seat back frame structural element in the molding of the composite seat back frame in the autoclave so that the diaphragm need not be applied during a separate manufacturing and assembly step. The composite seat back and seat diaphragm come out of the mold tool as a single structure. This technique can also enable the seat back to have the diaphragm in different positions in relation to the seat back frame.
Current manufacturing techniques typically involve manufacturing a seat back frame element out of aluminum, and separately manufacturing a fabric seat back diaphragm in the form of a sock, i.e., a fabric element with an open bottom. The diaphragm is pulled over the seat back by placing the diaphragm over the top of the seat back frame and pulling the diaphragm downwardly into its proper position. To provide a comfortable and resilient seat back, the diaphragm must be sized to be under tension after it is pulled over the seat back frame element. It is difficult to apply the diaphragm sock to the seat back frame under tension, and the diaphragm must be precisely the right size. If the diaphragm is too small it will not fit over the seat back frame or will tear either during or shortly after installation. If the seat back is too loose, the proper back support will not be provided to the seat occupant. Also, there is usually a complete hoop that goes around the front and back of the seat back frame. Molding the diaphragm into the seat back frame enables a single surface to be created, and using the techniques previously described, the surface can vary in depth. This will save weight and enable the formation of more comfortable seat backs based on designs based around the new technique described in this application. With the composite molded part arriving at the assembly station as a single unit there will be fewer parts, and no possibility of a mismatch in diaphragm and seat back frame delivery. This new technique can also be used in leg rests, seat pans, headrests and armrests.